Hello yiso91, and welcome to the friendly Camera Labs forum!
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As to your Q regarding resolution: There is an eternal struggle about how many pixels are enough. But as Gordon pointed out in his review, the lower resolution of the newer camera made good for some of the draw-back of the FZ100: Better image quality!
Many beginners (and also some seriously experienced folk) do pixel-peeping at their monitor at 100% magnification and in this case the FZ150 sports the "better pixels" than the FZ100.